Effect of microRNA-203 targeting regulation of Bmi-1 on proliferation and invasion of papillary thyroid cancer / 中华内分泌外科杂志

ABSTRACT

Objective:To investigate the expression of mBmi-1 in papillary thyroid cancer (PTC) and to analyze its relationship with clinical features of PTC and its mechanism.MethonsA total of 60 tissue samples were collected from Jun. 2018 to Dec. 2018 in Department of Oncology Surgery of Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine. Real-time quantitative polymerase chain reaction (RT-PCR) was used to detect the expression level of B cell-specific MLV integration site-1 (mBmi-1) in PTC tissues and its relationship with pathological features was analyzed. Bmi-l microRNAs (miRNAs) were predicted by bioinformatics sites targetscan and microRNA.org and confirmed by luciferase reporter gene experiments. CCK-8 (Cell Counting Kit-8) kit and Transwell chamber were used to measure changes in PTC proliferative capacity and invasive ability.Results:In this study, we found that mBmi-1 expression was positively correlated with PTC lesion size and invasion ability. Bioinformatics prediction results suggested that Bmi-1 was a target gene of microRNA-203 (MicroRNA-203, miR-203) , and the 3’-UTR target sequence of miR-203 against Bmi-1 was GUAAAGU. After transfection of the miR-203 mimetic, the expression of Bmi-1 mRNA in the PTC cell line TPC-1 was significantly down-regulated. The dual luciferase reporter gene assay demonstrated that miR-203 can act on the 3’UTR region of the Bmi-1 gene to predict the target. In addition, the transfection of miR-203 mimetic effectively inhibited the proliferation and invasion of PTC cells, and the ability of proliferation and invasion of PTC cell TPC-1 was restored after overexpression of Bmi-1 in PTC cell TPC-1 transfected with miR-203 mimic.Conclusions:Bmi-1 is positively correlated with the proliferation and invasion ability of PTC. miR-203 can inhibit the proliferation and invasion of PTC cells by directly targeting Bmi-1 gene.